Numbers 8:25

And from the age of fifty years they shall cease waiting upon
the service [thereof]
The heavy service of it: and shall serve no more;
by bearing and carrying the vessels of the sanctuary upon their shoulders, as Jarchi interprets it; this, according to the Jewish writers, was only in force while the tabernacle was in the wilderness, and was moved from place to place: but when it had a fixed habitation, and that laborious service of bearing and carrying the vessels of it ceased, years made no difference in the Levites, or disqualified them for service; for it is said ^F24, that the Levites were not bound by this law, but in the time of the tabernacle; but when it was at Shiloh, and at Jerusalem, where there was no bearing and carrying upon the shoulder, the Levites were not rejected on account of years, only for their voice, when they had lost that, and could not sing.